Identity

There is no information on when 'Abd Allah b. al-Hasan (a) was born, but it has been reported that he had not yet reached puberty when he was martyred. Some believe his mother was the daughter of Salil b. 'Abd Allah, sister of Jarir b. 'Abd Allah al-Bajali, while others have simply reported that his mother was a slave without naming her. He was martyred during the event of Karbala while defending his uncle, Imam al-Husayn (a).

Martyrdom

"Then, 'Abd Allah b. al-Hasan, who had still not reached puberty, left his tent and went to his uncle. Lady Zaynab went after him to took him back, and Imam al-Husayn (a) also told her to stop him, but 'Abd Allah strongly objected and said, "By God, I shall not separate from my uncle".

Abjar b. Ka'b set to attack Imam al-Husayn (a) with a sword. 'Abd Allah addressed him, "Woe to you oh impure offspring, do you want to kill my uncle". Abjar attacked with his sword and 'Abd Allah brought his hand forward [and the sword hits his hand], and his hand hanged from his skin. At this point Imam al-Husayn (a) hugged him and said, "Oh son of my brother, have patience and see this event as a good bode for yourself, for God shall unite you with your righteous fathers."

References

The material for this article is mainly taken from عبدالله بن حسن in Farsi Wikishia.